WTF Is up with my S14. Cooling problem.

[Pento240sx]

Hello again. So I change my bypass hose in the middle of the intake manifold (So had to remove the top part) so after that put everything together (Checked twice everything and all good). So now the problem is that when I changed my thermostat for the first time in 5 Years, to my surprise is when I open the water outlet, there was no thermostat, so I put a new one in. Now the problem is that when I drive the car for about 2 miles the gauge goes all the way to H and the comes back down to the middle. Also what I seen is that the water is boiling in my reservoir. So does anybody know what could be the problem?

Cliff Note: Change bypass hose (Between Manifold) put new thermostat. Temp gauge goes up and down and water bubbling in the reservoir tank, what could it be?

Thanks.

[-RJ-]

I am assuming you bled the system after installation. When you put the thermostat in, did you put the little hole at the 12 o'clock position?

[Pento240sx]

Negative on both. Do I have to put it that way? I remember putting it at 4 o'clock position.
BTW: I like your Yuno avatar. MM! FTW

[240hatchsx]

Since you didn't bleed the system of air it's getting trapped in certain areas of the block or rad and causing no cooling flow that's why the needle is bouncing for H to normal that quickly and sending boiling hot coolant into ur reservoir tank bc that's the only way the pressure build up can go. So after you set the Tstat in the up right position then make sure you bleed the system properly then it will run like a champ!

[costa_rican13]

this!!^ and then you'll be set.

[Pento240sx]

I see. Well I will try both. I will let you guys know how it run after wards. I really appreciate the help. Thanks.

[Dittoz7]

These things are a pain in the mule to bleed.

[alms24sebring]

Yeah mine still overheats every now and then for some unknown reason.

If anything at all, you must put the forget-what-you-call-it hole at 12 o'clock. But youll have to bleed it anyways and yes it's a pain because you never get all of it. You probably have major air pockets since you didn't bleed it.

[Pento240sx]

Well I did everything above and is still overheating. Could the water pump be it? Radiator cap?.
I hear a wining noise but I don't know if is the water pump or alternator, and I could hear it louder if I step on it. Is not the belt for sure.

[Dittoz7]

If it's a screeching sound like shredding soda cans in the sink disposal, water pump. Also if check to if you hear a hiss of any kind when it is over heating. Found out no to long about my radiator cap's rubber part wrapped and wasn't sealing.

[SBC 240Z]

I don't know if the DOHC water inlet and outlet are the same as the SOHC engine but I have made the dumbass mistake of hooking the hoses up backwards on the motor. This in turn meant that the engine was trying to pull water from the top of the radiator and send it to the bottom. It was a simple mistake from me getting in a rush but. it's unlikely the cause of your problem but it's worth a look. On the SOHC the water inlet and outlet are right next to eachother so if yours is the same way it's possible the previous owner had them off for some reason, got them swapped around accidentally and figured the overheating was from the thermostat and took it out.


*Edit* and just to be clear, if the coolant system is completely full the car will actually run at normal operating temps under most conditions. I drove around for a little while with the hoses backwards and only realized my error when the car started randomly overheating.

[srpowered240sx]

youre water pump sounds shot, id put on a new cap and change the pump, cheap and easy.

[Dittoz7]

Has anyone had success with cheaper non-oem nissan water pumps?

Nissan: $75
After-market: $25-30ish

Just wondering.

[SBC 240Z]

I'm using the cheapo autozone pump, it was like $23 and has been working good for two years

[S13_RB25]

Yea me too! Im using a duralast water pump, from autozone its ~$30, and its doing its job perfectly!

[Pento240sx]

I sometimes don't get my s14. Well I figure out was the problem (left a piece of paper towel in the bypass hose ) and it seemed that it fixed itself, haven't had problems since then. Anyways I decided that I am just going to change the water pump, because the noise is making, annoys me. I do appreciate the input and help. Thanks to all.

[SBC 240Z]

Nissans will break and fix themselves from time to time. Typically when one of mine breaks I give it a little while just to make sure it isn't going to sort itself out

[Dittoz7]

Well now that I'm running coolant (opposed to water) hopefully the water pump will stfu. If not glad to know it's not uber rare and costly part. gracias muchachos!